# Axis2HttpTargetRespListener.java

    /*
     *  Copyright (c) 2022, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
     *
     *  WSO2 Inc. licenses this file to you under the Apache License,
     *  Version 2.0 (the "License"); you may not use this file except
     *  in compliance with the License.
     *  You may obtain a copy of the License at
     *
     *  http://www.apache.org/licenses/LICENSE-2.0
     *
     *  Unless required by applicable law or agreed to in writing,
     *  software distributed under the License is distributed on an
     *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
     *  KIND, either express or implied.  See the License for the
     *  specific language governing permissions and limitations
     *  under the License.
     *
     */
    package org.apache.synapse.transport.netty.sender;

    import org.apache.axis2.context.MessageContext;
    import org.apache.axis2.transport.base.threads.WorkerPool;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.synapse.transport.netty.BridgeConstants;
    import org.apache.synapse.transport.netty.config.TargetConfiguration;
    import org.apache.synapse.transport.passthru.ErrorCodes;
    import org.wso2.transport.http.netty.contract.HttpConnectorListener;
    import org.wso2.transport.http.netty.message.HttpCarbonMessage;

    /**
     * {@code Axis2HttpTargetRespListener} listens for the response expected for the sent request.
     */
    public class Axis2HttpTargetRespListener implements HttpConnectorListener {

        private static final Log LOG = LogFactory.getLog(Axis2HttpTargetRespListener.class);

        private final MessageContext requestMsgCtx;
        private final WorkerPool workerPool;
        private final TargetConfiguration targetConfiguration;
        private final TargetErrorHandler errorHandler;

        public Axis2HttpTargetRespListener(WorkerPool workerPool, MessageContext requestMsgContext,
                                           TargetConfiguration targetConfiguration) {

            this.workerPool = workerPool;
            this.requestMsgCtx = requestMsgContext;
            this.targetConfiguration = targetConfiguration;
            this.errorHandler = new TargetErrorHandler(targetConfiguration);
        }

        @Override
        public void onMessage(HttpCarbonMessage httpResponse) {

            LOG.debug(BridgeConstants.BRIDGE_LOG_PREFIX + "Response received");
            workerPool.execute(new HttpTargetResponseWorker(requestMsgCtx, httpResponse, targetConfiguration));
        }

        @Override
        public void onError(Throwable throwable) {

            LOG.error("Error while sending the request to the backend service or "
                    + "processing the response from backend service", throwable);
            if (requestMsgCtx != null) {
                requestMsgCtx.setProperty(BridgeConstants.INTERNAL_EXCEPTION_ORIGIN,
                        BridgeConstants.INTERNAL_ORIGIN_ERROR_HANDLER);
                errorHandler.handleError(requestMsgCtx, ErrorCodes.SND_IO_ERROR, "Error in Sender", throwable);
            }
        }

    }